1. Field of the Invention
The invention relates to a focus control apparatus for use in imaging apparatuses having an exchangeable lens and a camera body. More particularly, the invention relates to a focus control apparatus and a focus control method, both designed to execute focus control by using a so-called hill-climbing method.
2. Description of the Related Art
Various techniques of achieving an accurate and high-speed automatic focus control have hitherto been proposed. Such a technique is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 10-322583. This technique is to interrupt the focus control of the hill-climbing method (hereinafter referred to as “hill-climbing AF”) for a predetermined time when the product of the angular velocity change of a lens unit and the focal distance exceeds a prescribed threshold value. The hill-climbing AF is achieved, first by detecting the contrast of the image acquired by an imaging element while moving the focus lens along the optical axis thereof, and then by detecting the focal position of the focus lens in accordance with the change in the contrast. If the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 10-322583 is utilized, the hill-climbing AF will be interrupted whenever a motion of the camera, including a pan, occurs. While the hill-climbing AF remains so interrupted, the focus control would not become unstable.